Mixing apparatus



June 12, 1956 w. LOEDIGE ET AL 2,750,163

MIXING APPARATUS Filld April 6. 1954 INVENTORS W/L #54 M AGED/6E FE/ 7' Z 4050/6 United States Patento MIXING APPARATUS Wilhelm Loedige and Fritz Loedige, Paderborn, Westphalia, Germany Application April 6, 1954, Serial No. 421,234

9 Claims. (Cl. 259-109) The present invention relates to mixing apparatus and in particular such apparatus which is designed for mixing granular, fibrous and pulverulent material.

In the United States Patent No. 2,679,385, dated May 25, 1954, a mixing apparatus has been disclosed which comprises substantially a vessel to receive the material to be mixed and which contains agitating and impelling means rotatable in the vessel for mixing the material. The agitating and impelling means disclosed in the said application comprise double-sided ploughshare-like elements, each of which is tapered towards its front and comprises a body of substantially triangular cross-section, the peripheral face and the two side faces of the body forming continuously smooth surfaces, whereby the said peripheral face is convex and tapered in the direction of its front end, while the said side faces are concave and symmetrically disposed.

It has been found that, depending upon the type of material to be mixed, the agitating and impelling means may be of a design different from that disclosed in the said application.

It is, therefore, one object of the present invention to provide a mixing apparatus which permits of rapid and intensive mixing of the material to be mixed, whereby the agitating and impelling means may assume a different shape depending upon the material to be mixed.

It is another object of the present invention to provide a mixing apparatus comprising a vessel in which a rotating shaft carries a plurality of impelling means which in combination with friction sheets disposed in the housing bring about a rapid and complete mixing of the material to be mixed.

With these and other objects in view which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawing in which:

Figure 1 is an axial section through the end portion of the vessel;

Fig. 2 is a section along the lines 22 of Fig. 1;

Fig. 3 is an axial section through the vessel disclosing a first embodiment of the impelling means;

Fig. 4 is a section along the lines 4-4 of Fig. 3;

Fig. 5 is an axial section through the vessel disclosing a second embodiment of the impelling means;

Fig. 6 is a section along the lines 6-6 of Fig. 5;

Fig. 7 is an axial section through the vessel disclosing a third embodiment of the impelling means as well as through the entrance hopper; v

Fig. 8 is a section along the lines 8-3 of Fig. 7; and

Fig. 9 is a section along the lines. 9 -9 of Fig. 7.

Referring now to the drawing, the present device comprises a vessel 1 in which a shaft 2' is rotatably mounted and any convenient means may be provided to rotate the shaft 2. The shaft 2 carries, a plurality of arms 3 which are axially and angularly displaced relative to each other.

A plurality of friction sheets 4 are disposed in the vessel 1, preferably between each pair of adjacent impelling means, which friction sheets 4 are of substantially ring shape and extend over the entire inner periphery or a part thereof of the vessel 1. The friction sheets 4 may be secured to the inner wall of the vessel 1 by spot welding or any other suitable conventional means.

As previously indicated, the impelling means may be of different design depending upon the particular material subjected to the mixing process. The impelling means shown in Fig. 1 comprises a substantially ring-like scoop 5, the outer edge of which is disposed in its axial projection in the vessel 1 to an erect a circle which is substantially concentric to the circle formed by the crosssection of the vessel 1. As clearly shown in Fig. 1, the scoop 5 extends in diagonal arrangement along the vessel 1 and is secured to the arm 3 for common rotation therewith. As clearly shown in Fig. 1, one end portion 5a of the scoop 5 is bent substantially into a plane extending perpendicularly to the longitudinal axis of the vessel 1 and, since all friction sheets 4 are disposed likewise in a plane extending perpendicularly to the longitudinal axis of the vessel 1, the end portion 5a is substantially parallel to the adjacent friction sheet 4 and extends close thereto. Upon rotating the scoop 5, the material to be mixed disposed in the vessel 1 is moved in sideward direction and a portion of the upper layers of the material is thrown by the scoop 5 upon emerging from the material in upward and sideward direction into the upper empty space of the vessel 1. Due to the close vicinity of the end portion 5a of the scoop 5 to the friction sheet 2, any existing larger particles are pulverized and thereby a very fine mixture of all ingredients of the material is brought about without permitting the formation of lumps.

Referring now to Figs. 3 and 4, the scoops 6 thus provided in this embodiment are formed as Wedge-shaped hollow bodies, the axial projection of which is substantially identical with that of the formerly described scoop 5, namely forming a ring portion concentrically arranged to the vessel 1. The side end portions of the scoop 6 have again extensions 6a which are disposed in planes substantially parallel to the friction sheets 4. As clearly shown in the center scoop 6 of Fig. 3, the side faces of the wedge-like hollow body are disposed in planes which extend at an angle to the longitudinal axis of the vessel 1. Upon rotating the scoop 6 at a predetermined velocity, the plain side faces of the scoop 6 throw the material to be mixed toward both sides and one portion of the upper layers of the material will be thrown upwardly to the empty space of the vessel 1. At the places where the friction sheets 4 are provided, the material to be mixed is subjected to friction between the spattle-like striking faces of the scoops 6 and the friction sheets 4.

Referring now to Figs. 5 and 6, this embodiment provides two scoops 7 and 7 secured to each arm 3, which scoops '7 and 7 are disposed radially spaced apart from each other. Both scoops 7 and 7 form in their axial projection again a ring-like configuration, yet as clearly indicated in Fig. 5, the scoop 7 forms an acute angle towards the arm 3 on the other side of the latter. This arrangement brings about a drive of the material in opposite directions and achieves a particularly extensive mixing of the material. This arrangement is preferably used for rnateral not easily mixed because it provides a stirring, throwing, and feeding effect and in combination with the friction sheets 4 also a good friction effect. The scoops 7 and 7' are preferably of slightly convex shape towards the vessel 1. Upon rotating the scoop 7, the material is lifted from the vessel wall and during its run through the material moves the latter sidewardly in different directions and upon emerging from the material throws the latter again in upward direction into the empty space of the vessel 1. Preferably, the arms 3 are spaced apart on the shaft 2 in such manner that all scoops 7 and all scoops '7 form upon rotation an interrupted spiral line. The scoop 7 operates close to the inner wall of the vessel 1 so that the latter still operates at least in one direction (according to the showing in Fig. 5 to the left) even if a small amount of material to be mixed only is present in the vessel 1. As indicated above, the scoops '7', which are disposed closer to the axis of the vessel 1, are arranged in such manner that they feed in a direction opposite to that of the scoops 7, thereby providing a substantially constant throwing height of the material to be mixed even if the upper level of the material exceeds a predetermined filling height, thereby rendering operative under all circumstances the scoops 7. The end portion 7a of the scoop 7 exerts a friction effect upon the material to be mixed in combination with the friction sheets 4.

Referring now to Figs. 7 to 9, the scoops 8 have substantially a double ploughshare configuration. The pointed front end of the scoops 8 move closely adjacent to the inner wall of the vessel 1 and the distance between the scoop 8 and the inner wall of the vessel 1 increases towards its rear end. The particular configuration of the scoop 8 is designed to loosen up the material to be mixed and to increase the capacity of throwing the material into the empty upper space of the vessel 1 and, thereby, to increase the exactness of the mixing of the material in the shortest possible time. The side walls of the scoop 8 are of concave shape and terminate rearwardly in striking faces 8:: which are disposed substantially parallel and close to the friction sheets 4. The scoops 8 may be left open on the outer periphery or may have a closing wall extending from the front point towards the rear end of each of the scoops 8. The scoop 8' disposed at the front end of the vessel 1 is designed similarly to the scoop 8 with the exception that it forms only half of a ploughshare, that means, a concave wall extends only from one side of the arm 3. Nevertheless, the scoop 8 lifts the material to be mixed from the end piece and throws the same in axial direction into the upper empty space. A similar cooperation with a friction sheet 4 is provided as has been set forth in connection with the previously described embodiments of the different scoops.

The friction sheets 4 may be disposed along the entire inner periphery of the vessel 1 or only along a part thereof, as already indicated above, depending upon the type of material which is to be mixed. The friction sheets 4 may further have plain surfaces, as shown in the embodiment disclosed in Fig. 4 or they may be equipped with roughened surfaces, as for instance shown in Fig. 6, or for particular material to be mixed, it may be advantageous to provide a plurality of perforations in the friction sheets 4 as particularly indicated in Figs. 2, 8 and 9.

The vessel 1 may be equipped with a hopper 9 at one of its ends, which hopper 9 is adapted to feed material to be mixed into the vessel 1. The other end of the vessel 1 has an end wall 1a to which a housing 10 is secured which is open at its bottom for removal of the mixed material.

The end wall 1a is equipped with a longitudinal, vertically disposed opening 11. and guide means (not shown) may be secured along the longitudinal edges of the opening 11 for receiving a slide 12 of a length slightly greater than that of the opening 11. The slide 12 covers the opening 11 completely in its middle position 11, while its moving into its uppermost position I permits the complete emptying of the vessel 1 and the downward movement of the slide 12 into the position III determines the operating level of the material to be mixed in the vessel 1, whi h position Ill is set for continuous operation of the device. Since the present mixer operates in accordance with the throwing principle, the level of the material to be mixed remains the same despite the continuous feeding of material at one side and the said removing level by proper setting of the slide 12 on the other side. This level may be controlled, of course, by raising or lowering the slide 12.

The mixer, in accordance with the present invention, operates in the following manner: The pointed and concave shaped side faces of the scoops lift the material to be mixed from the wall of the vessel 1 and loosens the material thoroughly, which is an essential pre-condition for a thorough mixing of the material. In case lumps should appear in the material fed into the vessel 1, the cooperation between the scoops and the friction sheets 4 loosens up the greatest part of such lumps. The scoops 7, which provide a stirring, throwing and feeding effect, are used particularly in those instances where the mixing vessel 1 has a length which is preferably greater than that of its diameter, a structure particularly used in large mixers or where such structure is necessary for mixers operating continuously for reasons of available space. Despite the length of the mixing vessel, the material to be mixed will move, nevertheless, very fast through the vessel from the hopper to the other end. A continuous mixing neutralizes also any irregularities in the continuous feeding of the material to be mixed.

The scoops 6, which have straight side faces, are preferably used in such instances where the material should be subjected to an increased frictional force brought about by the centrifugal force of the scoops 6. The material to be mixed cannot escape too easily and is subjected to high pressure during the rotation of the scoops 6.

In order to permit free access to the friction sheets 4, one portion 1' of the vessel 1 is formed removable from the remaining part of the vessel and hinge means 13 may be provided at one end of the portion 1' in order to hingedly secure the portion 1 to the vessel 1, while the other end of the portion 1 is equipped with an extension 14 having a boring 15 adapted to receive a screw-bolt 16 extending from the vessel 1 which receives preferably a wing-nut 17 to be screwed on the screw-bolt 16 and, thereby, to secure the portion 1' in a vessel closing position.

While I have disclosed several embodiments of the present invention, it is to be understood that these cmbodiments are given by example only and not in a limiting sense, the scope of the invention being determined by the objects and the claims.

I claim:

1. In a mixing apparatus, a vessel for containing material to be mixed and a shaft rotatably mounted in the said vessel, a plurality of arms extending radially from the said shaft, the said arms being axially and angularly spaced apart from each other, agitating and impelling means constituting mixing elements secured to said arms, and a plurality of friction sheets forming at least a portion of a ring-like member disposed parallel to and axially spaced apart from each other in a plane substantially perpendicular to the longitudinal axis of said shaft and secured adjacent the said mixing elements to the inner wall of the said vessel, and the said mixing elements forming side sheets disposed parallel to and adjacent the said friction sheets, in order to bring about cooperation between the said side sheets of the rotating mixing elements and the immovable corresponding friction sheets and to permit throwing of the material to be mixed within the said vessel to both sides of said friction shcets without interference of the latter.

2. The mixing apparatus, as set forth in claim 1, in which the said mixing element comprises a wedge-shaped double-sided body of substantially triangular cross-section formed complementary to the inner face of the said vessel, the side faces of the said body being disposed in two planes forming a sharp acute angle, and the forward end of the said body being formed to a point, the said side faces being extended to form said side sheets disposed parallel and adjacent to the said friction sheets.

3. The mixing apparatus, as set forth in claim 1, in which the said mixing element comprises a single-sided body formed complementary to the inner face of the said vessel, the single face of the said body being dis posed in a plane forming a sharp acute angle to a plane extending perpendicular to said shaft, said side face being extended to form said side sheet disposed parallel and adjacent to said friction sheet.

4. The mixing apparatus, as set forth in claim 1, in Which the said mixing element comprises a wedge-shaped double-sided plow-like body of substantially triangular cross-section, open at its rear and formed complementary to the inner face of the said vessel, the side faces of'the said body being of concave shape towards the outside of said body, and the forward end of the said body being formed to a point, the said side faces being extended to form said side sheets disposed parallel and adjacent to the said friction sheets.

5. The mixing apparatus, as set'forth in claim 1, in which the said mixing element comprises a single-sided body formed complementary to the inner face of the said vessel, the single face of the said body being of concave shape towards the outside of said body and disposed in a plane forming a sharp acute angle to a plane extending perpendicular to said shaft, said side face being extended to form said side sheet disposed parallel and adjacent to said friction sheet.

6. The mixing apparatus as set forth in claim 1, in which the said mixing element comprises a double-sided body of spiral form, the axis of the said spiral being identical with that of the rotating axis of the said mixing element.

7. The mixing apparatus, as set forth in claim 1, in which the said friction sheets have roughened surfaces.

8. The mixing apparatus, as set forth in claim 1, in which the said friction sheets have a plurality of perforations.

9. The mixing apparatus, as set forth in claim 1, in which the said friction sheets have a rasped surface.

References Cited in the file of this patent UNITED STATES PATENTS 219,945 Hogan Sept. 23, 1879 275,319 Allen Apr. 3, 1883 277,319 Miller May 8, 1883 284,487 Roger Sept. 4, 1883 661,796 Ernst Nov. 13, 1900 1,101,104 Swane June 23, 1914 1,222,584 Barr Apr. 10, 1917 1,760,906 Johnson June 3, 1930 2,240,841 Flynn May 6, 1941 

